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In today’s scenario, both in gasoline and diesel engines, it is important to reduce power consumed by the auxiliary devices causing parasitic loss. Oil pump is one such device, used for lubrication purpose, which consumes higher power developed by the engine causing parasitic loss. Conventionally gerotor construction pumps are predominantly used in majority of engines, owing to its simpler construction, lower NVH and cost. However, this type being a positive displacement pump, consumes higher power with increase in speed. Hence, variable displacement oil pumps are gaining importance as the oil flow rate can be varied over the entire engine operating range. In this work, basic design elements of variable displacement oil pump are identified followed by building of mathematical model to calculate the critical design parameters. The basic mathematical model built can calculate oil flow rate, leakage losses and power consumption at different speed and load conditions.

As India has decided to move to BS VI emission regulation by 2020, all original equipment manufacturers (OEM) and Tier 1 suppliers are working towards achieving the goal. Overall reduction in CO2 reduction can be achieved through power to weight reduction of various power train components. In a conventional Multi Point Fuel Injection (MPFI) engine, a fuel rail or delivery pipe is mounted on the intake manifold or cylinder head, which delivers fuel to inlet port at a fuel pressure of 350 kPa to 400 kPa through fuel injectors. In today’s automotive industry most of the fuel rail components are made through PDC process of aluminium because of its ease of availability and machinability. Therefore, several studies have focused on alternate materials like sheet metal and plastic by reducing the weight of the fuel rail. Sheet metal fuel rails can also be made with significant weight reduction. However, their manufacturing processes are complex.

Electric coolant pump and electric coolant circulation pumps are one of the main auxiliary devices that can be used to cool the power train components and other accessories such as cabin heating, battery cooling and electronic circuits cooling. Design process of electric coolant pump starts with the target requirement of flow input, which is used to calculate the torque, speed and power of the motor to arrive at the motor specifications. In this overview, the concept of radial field motor and claw pole motor are taken for study. The design of critical parameters of the stator core and its optimization to reduce the core loss, torque ripple is emphasized. The stator core material selection and the appropriate manufacturing methods are explained in detail which allows the designer to optimize the stator core design in terms of performance, cost and compactness.

The main challenge in today's modern engines is to design the parts, which should withstand higher temperatures. To achieve this, selection of materials and process tolerances are very important factors. The product identified in this study is a conventional oil pump, which is an engine auxiliary component. The function of the oil pump is to supply oil to different parts of the engine to lubricate and reduce the overall engine friction. The different speed and load conditions for which the engine is subjected, pose a challenge to the oil pump, to supply the necessary quantity of oil at the required pressure and temperature. Normally, the oil pump is subjected to a temperature of 120°C at higher speeds. However, the peak oil temperature in modern diesel engines can be as high as 140°C to 150°C for a short period of time. For this study, two engine grade oils were selected. Numerical analysis was performed to predict the oil flow rate for these oil grades.

In gasoline direct injection (GDI) engines, air-fuel mixture homogeneity plays a major role on engine performance, especially in combustion and emission characteristics. The performance of the engine largely depends on various engine operating parameters viz., start of injection, duration of injection and spark timing. In order to achieve faster results CFD is becoming a handy tool to optimize and understand the effect of these parameters. Therefore, this study aims on evaluating the two injection parameters viz., single and split injection to evaluate different flame characteristics. Novelty in this study is to define five different parameters which are called α, β, γ, δ and η the details of which are explained in the paper. In order to understand the flame characteristics, these five parameters are found to be very useful. In the present study, a single-cylinder, two-valve, four- stroke engine which is used in two-wheelers in India is considered for carrying out the CFD analysis.

Gasoline direct injection (GDI) technology is already in use in four wheeler applications owing to the additional benefits in terms of better combustion and fuel economy. The air-assisted in-cylinder injection is the emerging technology for gasoline engines which works with low pressure injection systems unlike gasoline direct injection (GDI) system. GDI systems use high pressure fuel injection, which provides better combustion and reduced fuel consumption. It envisages small droplet size and low penetration rate which will reduce wall wetting and hydrocarbon emissions. This study is concerned with a CFD analysis of an air-assisted injection system to evaluate mixture spray characteristics. For the analysis, the air injector fitted onto a constant volume chamber (CVC) maintained at uniform pressure is considered. The analysis is carried out for various CVC pressures, mixture injection durations and fuel quantities so as to understand the effect on mixture spray characteristics.

In modern direct injection gasoline engines, air-fuel mixing has a strong influence on combustion and emission characteristics, which in turn largely depends on in-cylinder fluid motion. However, in-cylinder fluid motion dependent on many engine parameters viz., piston shape, engine speed, intake manifold orientation, compression ratio, fuel injection timing, duration, etc. Among them, piston shape has significant influence on the in-cylinder fluid motion. Therefore, this study aims on evaluating the effect of piston shape on in-cylinder flows in a direct injection engine using CFD. In this study, a single-cylinder, two-valve, four-stroke direct injection engine designed for two-wheeler application in India is considered for the analysis. ‘STAR-CD’ and és-ice’ are used for CFD analysis. Pressure boundary values obtained from measurements in the actual engine are employed. Two piston-shapes viz., flat and bowl types at wide-open-throttle under non-firing conditions are considered.

In India, for two-wheeler application, carburettor is the preferred fuel supply system for majority of the market, owing to its simplicity and low cost. With the regulations becoming stringent, carburettor internal structure requires modification. One of the important parameters is the venturi shape, which controls the air-fuel mixture supply to the engine. Venturi shape plays an important role in deciding the transient performance characteristics. In this study, a CFD analysis has been carried out to predict the pressure and velocity at the venture of the carburettor. Four different cross sections namely, circular, oval, trapezoidal and double D venturi shapes were selected. The geometric model of the carburettor was created and mesh refinements were carried out in critical regions. At part open throttle, CFD prediction of airflow rate with Trapezoidal venturi shape was found higher when compared to other venturi shapes.

In order to achieve good fuel spray characteristics, proper placing of the fuel injector in the intake manifold in port fuel injected (PFI) gasoline engines is very crucial. In automotive PFI engines, vehicle layout may be a constraint to mount the fuel injector in best possible location and inclination. In general, PFI engines use straight spray fuel injection. However, if there is a vehicle layout constraint, then inclined fuel spray may be suitable which is not very common. Hence, it is important to understand the effect of fuel spray inclination on fuel spray characteristics. In this study, a CFD analysis has been carried out for the four inclinations of fuel spray and the results are compared. The geometrical modeling of the fuel injector is done using ProE software. It is meshed with polyhedral cells and mesh refinement is done wherever required. Inlet air velocity and exit pressure of intake pipe at wide-open-throttle conditions are used as boundary conditions.

Vacuum pumps are predominantly used in diesel engines of passenger cars and trucks for generating vacuum in servo brake applications. With the emission norms getting stringent, there is a need for vacuum signal for EGR actuation, turbo-charger waste gate actuation and other servo applications. These multi-functional applications of vacuum pumps and the functional criticality in application like braking system demand an effective and reliable performance. In gasoline engines, the vacuum generated in the intake manifold is tapped for braking. The recent technology of gasoline direct injection compels the use of vacuum pump in gasoline engines also due to scarce vacuum in intake manifold. The performance of the vacuum pump is highly dependent on the opening and closing of the check valve sub-system, which is positioned between the vacuum reservoir and the pump at the suction side.

Vacuum pump is a device which gets the drive from engine cam shaft. In some designs, it is driven by the alternator shaft. The main function of vacuum pump is to evacuate the air from the brake booster tank, thus creating vacuum, which can be used for brake application. In addition to this, in new generation engines, to meet the Euro V emission targets, vacuum pump also has to create vacuum in the auxiliary tank which will be used to actuate the turbo charger waste gate actuation mechanism and EGR valve. The vacuum pump used for brake application when modified to perform the additional function of turbocharger may deteriorate the primary application performance. The tapping position and the size of the vacuum port for the auxiliary tank will influence the primary braking performance of the pump. The work described in this paper involves the systematic analysis of layout study of vacuum pump to meet the performance of the vehicle for brake and turbocharger applications.

The main challenge in designing the oil pump for gasoline & diesel engines is to optimize the pressure relief passage. Pressure relief passage is critical from design point of view as it maintains the oil pressure in the engine. Optimal levels of oil pressure and flow are very important for satisfactory performance and lubrication of various engine parts. Low oil pressure will lead to seizure of engine and high oil pressure leads to failure of oil filters, gasket sealing, etc. Optimization of pressure relief passage area will also reduce the power consumed by the pump. The Pressure relief system for this study consists of Pressure relief valve, spring, retainer, pressure relief passages. It is difficult to directly measure the flow through the pressure relief passage and is arrived based on the drop in flow at the delivery port. Numerical tool will be handy to predict the flow through the pressure relief passage and this can be used to optimize the flow through the bypass passage.

Emerging trend in the automotive industry all around the world is to develop vehicles to consume less fuel and to meet stringent emission norms by using engines of higher power to weight ratio and higher thermal efficiency. These advanced technology engines designed for high power output will use low viscous oil to reduce frictional losses and will operate at elevated temperature levels. Hence, the various auxiliaries and parts of these engines should be adaptable for the use of low viscous oil and should withstand higher temperatures. Oil pump is one such auxiliary which will be subjected to work with low viscous oil at higher temperatures levels. The oil pump taken for study and design improvement is an internal gear type positive displacement oil pump, used in a passenger car diesel engine. The un-meshing of the gears causes the inflow and meshing causes the outflow of lubricating oil. This process occurs continuously for providing a smooth pumping action.